Missouri Gov. Eric Greitens should resign — not because of an extramarital affair, but because he is just another political poser.

The hard-charging Republican swept voters off their feet with his Hollywood good looks, Rhodes Scholar and Navy Seal pedigree, and a campaign fueled by righteous indignation over the corrupt politicians soiling our state’s Capitol.

He was on a mission to take back our state from evil career politicians — the overwhelming majority from his own party – and instill conservative values to an institution that had been rocked by too many scandals.

He would return honor, decency and transparency to public service. It would take an outsider to clean up this mess, someone with integrity and courage. He was the patriot to get the job done.

We got hoodwinked. A year after taking office, our governor is drowning in humiliation, the Capitol is roiling in scandal, and Missouri is making national headlines again for all the wrong reasons.

To be clear, Greitens ceded the moral high ground long before this week’s stunning story broke of his affair and allegations of blackmail.

He campaigned on transparency and accountability, but has been the most secretive governor in modern history.

He has refused to disclose the sources of “dark-money” campaign contributions, the amounts donors gave to his inauguration festivities and even routine things like his daily schedule and travel logs.

Greitens was fined by the Missouri Ethics Commission for failing to report the use of a fundraising list and is currently being investigated by Missouri Attorney General Josh Hawley for using a phone app that automatically deletes text messages.

Our governor eschews career politicians but has spent considerable time flying around the country in what appears to many to be an ongoing audition for higher office.

He avoids answering difficult policy questions by evading the press, preferring instead to use social media to stay on message with carefully crafted sound bites.

This was before a television station broke a story Tuesday that Greitens had an affair with his hairstylist shortly before he was elected and allegedly blackmailed her by taking a photo of her while partially undressed.

Greitens acknowledged the affair but denied the blackmail accusations. The incident is being investigated by law enforcement authorities, which will likely drag on for months, casting more ominous clouds over the Capitol.

Whatever the outcome of this latest incident, this much is clear — Greitens isn’t the righteous, virtuous person he projected in his campaign.

Few politicians live up to the hype created by a campaign, but Greitens is looking more and more like the corrupt politicians he spoke out against.

Regardless, his ability to govern is irreparably damaged by this latest scandal. He should do what is right for his party and for Missouri and step down. Lt. Gov. Mike Parson is more than capable of leading the state.